Diversity and Antimicrobial Attributes of Fungal Endophytes from Argemone mexicana L.

Abstract

Aims: The medicinal herb Argemone mexicana L. possess significant medicinal values and being used to treat various infections. The research on exploring endophytic fungal diversity of the A. mexicana and their pharmacological applications remains limited. This study aimed to investigate the diversity of endophytic fungi in A. mexicana and to determine their antimicrobial capacities. Study Design:  The study included the isolation of endophytic fungi from the plant Argemone mexicana and determination of antimicrobial activities of these fungi against selected targets. Place and Duration of Study: Department of Microbiology, Davangere University, Davangere, Karnataka, from August 2021 to February 2025. Methodology: The endophytic fungi of A. mexicana were isolated and identified. Fungal diversity assessment was done with Relative Abundance (RA%), Colonization Frequency (CF%), and Simpson diversity index. The evaluation of antimicrobial properties of these fungi was done through agar-well diffusion assay and conidial germination inhibition assay. The crude cellular and secretory extracts were analyzed for antimicrobial potentials through disc-diffusion assay, conidial germination inhibition assay, bioautography, and TLC-bioautography methods. Results: A total of 26 endophytic fungal isolates were recovered from stem, root, and leaf tissues. More diverse fungal assemblages were noticed in stem tissues. The Fusarium oxysporum was found as the dominant species with a Relative Abundance of 23.01%. Four isolates, Aspergillus luchuensis (DUMB 210 and DUMB 222), Penicillium dierckxii (DUMB 208), and Penicillium restrictum (DUMB 211) showed antifungal activity. The crude secretory extract of P. dierckxii was efficient against Gram-positive bacteria and all the target fungi. Only two TLC-separated fractions (F3 and F8) from the secretory extract of P. dierckxii showed antifungal activity. Conclusion: The findings of the present study highlighted the association of fungi as endophytes in A. mexicana. The potential of these endophytic fungi to produce antimicrobial metabolites was realized.